- Built with proprietary composite polymer to withstand extreme conditions- When most lowers dent or break the AR1 eXtreme bounces back to shape- 4.3oz Weight- Accepts all standard MIL SPEC uppers up to .50 Beowulf- Compatible with most current AR15 lower parts kits, grips and stocks- Unconditional lifetime warranty- Custom engraving – “The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants.”- Multi-Caliber Marked- Flat Dark Earth- 100% USA Made